Surgical wires and cables are used in a variety of surgical procedures, for example, reconstructive spine surgery such as fusions, spine trauma surgery, total hip arthroplasty, fracture fixation, open heart surgery for closures of the sternum, oral and facial surgery to fix mandibular fractures and the like, and other surgical procedures. Often, surgical cables and wires are used to encircle or loop about bones to hold them together for healing or fusion in some types of spinal surgery. For purposes of this application, "cable" includes monofilament and single strand wire along with multifilament and multistrand cable and wire ropes.
In some orthopedic procedures, it is desirable to provide a tensile force to selected portions of a patient's body such as two adjacent vertebrae. This is frequently accomplished by placing two loops formed of surgical cable about the vertebrae. In placing the loops, it is necessary to pass the cables under the lamina of the vertebrae (sublamina) to establish the desired tension in the cables, and then to attach the cables in loops. One method of accomplishing these tasks is for the surgeon to secure a suture to a midsection of a cable, pass the cable sublamina, and then cut the suture and cable so that two cables exist under the lamina of the patient. The cables can then be looped about the vertebrae and tightened by hand with surgeon plucking the cables to determine tension. After tightening, the surgeon secures the cables in their respective loops.
One method of securing the cables in their respective loops is to provide a permanent loop on one end of the cables. This method is accomplished by forming a small loop on one end of the cable and securing the small loop with a crimp, and then passing the end opposite the small loop through the small loop in an arrangement similar to a cowboy's lasso. Then a crimp member with a flange may be placed on the cable opposite the small loop end and slid along the cable until snug against the small loop member. Then after applying the desired tension, the crimp member may be crimped so that a secured loop is formed. This method involves two crimp members and has two parts of the cable resting against each other which may lead to increased wear of the cable and an increased likelihood of premature failure.
Another method is to provide a bar member with two transverse apertures. A stop member is attached to one end of the cable and then the other cable end is passed through one of the apertures until the stop rests against the bar member. The cable end opposite the stop member forms a loop and is then passed through the other aperture and then through a crimp member. The crimp member is placed snugly against the bar member and crimped once the desired tension is applied to the cable. Among the shortcomings of this method may be the difficulty in holding all the parts with surgical instruments during the procedure. Additionally, this method and the previously described method do not protect against fraying once the cable is cut. See U.S. Pat. No. 5,116,340, which is incorporated by reference for all purposes.
Therefore, a need has arisen for a surgical cable crimp that efficiently secures a surgical cable in a loop, uses a small number of parts, is easily handled by surgical instruments, does not allow the cable to rest against other portions of the cable, and helps prevent fraying.